In the past, many automotive dashboards were fabricated from a metal stamping which was polished and then painted. In an effort to improve vehicle occupant safety in crash situations, padding was added to the side of the dashboard that faced towards the vehicle's interior. To lower manufacturing costs and also to lower vehicular weight, padded metal dashboards were replaced with composite dashboards.
Composite dashboards have a preform. The preform is typically fabricated from a rigid plastic material or a wood fiber compound. A foam polymeric material covers the preform to provide for cushioning. Placed on top of the foam polymeric material is a polymeric multiform skin membrane, which typically has an outer surface to simulate a smooth textured appearance similar to that of leather. To fabricate such a composite dashboard typically the skin membrane is placed into a mold spaced away from the rigid preform. The material that provides the foam cushioning is then shot into the mold and adheres to both the preform and skin membrane to form a composite dashboard.
Prior to its placement into the mold to form the composite, the skin membrane is formed in a separate molding operation. To form the skin membrane, there is provided a rotatable mold cavity or envelope. The mold envelope is heated. Powdered thermal formable plastic feed-stock material is placed within a bucket. The bucket is moved laterally to a position placing it underneath an opening of the mold envelope. The bucket is then elevated and is aligned with the mold envelope via an arrangement of alignment pins on the bucket sliding into blocks on the mold envelope. A clamping mechanism then clamps the bucket to the mold envelope. A positioning mechanism that elevates the bucket to the mold envelope, is then lowered, and the mold envelope and bucket are rotated, allowing the powdered plastic feed stock to fall into, melt and adhere to the mold envelope to form a multiform skin membrane.
Although the aforementioned molding apparatus and process has been successfully utilized it presents several disadvantages. The bucket has to be moved laterally and vertically, which causes alignment problems in both movement processes. Also, the bucket is initially at a much lower level than the mold envelope during its lateral movement. Thus, the mold envelope has to be elevated (if it is desired to keep the bucket close to floor level or slightly above) or the bucket must be placed in a pit to allow it to be elevated to the mold envelope, which is positioned near floor level. The fact that the mold envelope and the bucket are often at two different elevations increases the capital costs of such a molding arrangement. A further disadvantage is the use of cycle time by the lateral and vertical movements of the feed stock bucket in joining it to the mold envelope.
It is desirable to provide a molding apparatus and method of utilization thereof that alleviates the aforementioned disadvantages when molding polymeric membranes.